This invention relates generally to a excavating machines, and more particularly to a trench-cutting machine that is adapted to cut through rock, dirt and/or pavement. More particularly, the invention relates to an excavating machine having a rotary cutting wheel that is mounted on a boom which is carried on a chassis.
It is often necessary to dig relatively narrow trenches to receive television cables, fiber optic cables, drainage lines and utility lines through packed earth, concrete, asphalt or even solid rock. Such materials are typically too hard to be excavated by conventional chain-type trenchers; however, trenchers of the rocksaw type have been found to be ideally suited for this task. The conventional rocksaw trencher includes a rotary wheel having a plurality of cutting teeth mounted around the periphery. The wheel is typically mounted on a boom that is disposed along the centerline of the machine between a pair of track assemblies. The boom is pivotally mounted to the chassis of the machine at one end. Such machines are described in U.S. Pat. No. 3,680,919 of Rear et al., U.S. Pat. No. 4,542,940 of Marten, U.S. Pat. No. 5,575,538 of Gilbert et al. and U.S. Pat. No. 5,809,670 of Yoder et al. The cutting wheels of most of these machines are hydrostatically powered, although the machines of Rear et al. and Yoder are chain-driven.
All of these prior devices include one or more disadvantages. For example, each of them is mounted to a boom that extends beyond the end of the chassis and is supported at only one end. When such a machine is operated to cut through material of varying hardness, such as rock embedded in dirt, the cutting wheel may tend to xe2x80x9cfloatxe2x80x9d or xe2x80x9cbumpxe2x80x9d upwardly when it encounters the harder material, thus producing a cut of non-uniform depth. In addition, mounting of the cutting wheel along or near the centerline of the machine prevents the machine from making a cut near a fence line, bridge support or other obstacle. Finally, the machines that are hydrostatically powered involve complex and expensive wheel-driving components, yet may have insufficient power to cut through hard rock at a reasonable rate. Furthermore, the chain-driven cutting wheels of Rear et al. and Yoder involve complex frame and roller assemblies, in addition to a chain and sprocket drive, that could be fouled or jammed by rocks and dirt produced during cutting.
It would be desirable if a rocksaw-type trenching machine could be developed that would avoid the disadvantages of the previously-known devices.
Among the advantages of the invention is the provision of a rocksaw trenching machine that includes a cutting wheel that is mounted within the main frame of the machine rather than extending off one end of the machine. Another advantage of the invention is the provision of such a machine having a cutting wheel mounted on a boom that may be supported by the chassis at both ends. Still another advantage of the invention is the provision of a rocksaw trenching machine that includes a cutting wheel that is mounted along one side of the machine. Yet another advantage of a preferred embodiment of the invention is the provision of such a machine that includes a simple mechanical drive for the cutting wheel. Another advantage of a preferred embodiment of the invention is the provision of such a machine having a cutting wheel that is adapted to cut downwardly as the machine is operated.
Additional advantages of this invention will become apparent from an examination of the drawings and the ensuing description.
The invention comprises a self-propelled trench-cutting machine which includes a chassis and a drive assembly mounted to the chassis for driving the machine along a surface to be cut. The machine includes a boom having a first end and a second end. The boom is mounted along a side of the chassis for pivotal movement about a pivot axis at the first end. A rock cutting wheel is mounted on the boom for rotation about a wheel axis, and means are provided for rotating the rock cutting wheel about the wheel axis. The machine also includes a locking mechanism that is adapted to lock the second end of the boom to the chassis.
In order to facilitate an understanding of the invention, the preferred embodiments of the invention are illustrated in the drawings, and a detailed description thereof follows. It is not intended, however, that the invention be limited to the particular embodiments described or to use in connection with the apparatus illustrated herein. Various modifications and alternative embodiments such as would ordinarily occur to one skilled in the art to which the invention relates are also contemplated and included within the scope of the invention described and claimed herein.